Aegis but it just works on Android. If possible use a 2FA app that is open source and doesnt't have internet connection.

I use vaultwarden/bitwarden

I use a keepass database with KeePassium (strongbox looks great too).

I keep the database in the cloud but it’s unlocked by a local keyfile on each device. So if it’s compromised they would need the keyfile.

KeePassium keeps a local copy and backups if you lose connection.

Not sure about syncing, but I use Aegis on Android and it works well

I you are willing to self host, 2FAuth is pretty good.

I use Pass (https://apps.apple.com/il/app/pass-password-store/id1205820573) which is an iOS version of pass (the command line password manager) that also supports pass’s 2FA extension.

2FAS or a KeePass vault kept in sync on both, which can store TOTP private keys and display them when needed.

keepassxc for desktop and for Android: FreeOTP+ (the plus is important)

I use KeePassXC and you can sync it with Syncthing. On iOS there are alternatives which a compatible with Syncthing and the KeePassXC database, it works very cool once you figure out how to do it and you also got all your passports synced too with it.

I use 1Password for mine.